Background: Dysmenorrhea is accompanied by abnormal brain metabolism in affective cortical-limbic structures; regions are functionally involved in nociceptive and olfactory processing. The study aims to examine the manifestation of chemical sensitivity changes in women with dysmenorrhea. Methods: A cross-sectional correlation research design was used for this study. Five subsets of odors (lemon, H2S, ethyl, acetone, and rose) were tested on 120 women. The visual analogue scale was presented to evaluate the intensity (strong to weak) and hedonic value (pleasant to unpleasant) of each odor. The participants underwent Pain index of dysmenorrhea questionnaire (DQ) and psychophysical assessment after performing olfactory tests. Results: (1) An increased unpleasantness rating of the H2S odorant was associated with the degree of dysmenorrhea. DQ-severity score was the statistical significance of the predictor variable on H2S odorant perception alteration (P =.006), after controlling the collinear variables from regression. (2) Lemon, acetone, and ethyl odorant as positive hedonic values recognized were not significantly related to the DQ pain scores. (3) Additionally, decreased perception of the intensity of the rose odorant was related to rising dysmenorrheal frequency level. (P =.015). (4) Women with higher DQ score were positively related to psychological distress such as anxiety, depression and stress level. Conclusions: Findings disclosed that significantly raised the unpleasantness level of odorant H2S, and weakening the intensity value of the pleasantness rose odorant relates to women with severe dysmenorrhea symptoms. The neurobiological bases of olfactory sensitivity changes refer to olfactory-limbic system disturbances and appropriate management of menstrual cramps were discussed.

Zald DHaJV: Pardo, Emotion, olfaction, and the human amygdala: amygdala activation during aversive olfactory stimulation. Proceedings of the National Academy of Sciences of the United States of America 1997, 94(8):p. 4119-4124.